Amputee teams up with biomedical engineer developing advanced prosthetic limbs to win top spot at this year's Cybathlon Challenges, an international assistive technology event, Yang Feiyue reports.

Xu Min would never have expected that, despite the misfortune of losing her right arm in an accident decades ago, she would become champion of a global contest.

The moment that Xu, in her 40s, heard the shrill beep, she sprang into action at the competition in Suzhou, Jiangsu province, on March 29.

Equipped with a robotic, forearm prosthesis, the woman looked like a warrior from a sci-fi movie. She quickly grabbed four large bottles full of liquid with her mechanical hand and placed them in a storage basket before moving the basket to the designated location.

Then, she wasted no time taking up a second round of challenges — to collect small beads, each with a diameter of 1 centimeter, and to insert keys and cards into their respective slots.

Again, Xu adroitly breezed through the tasks with zero slip-ups.

Her total time ended up being two seconds quicker than her nearest competitor, earning her the championship title at the Cybathlon Challenges 2023, which was streamed online on March 29.

Her title was achieved thanks to a team of experts from the Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, based in East China's Jiangsu.

The Cybathlon is an international assistive technology competition and rehabilitation event organized by the Swiss Federal Institute of Technology (ETH Zurich). It showcases the latest research achievements, encourages and supports teams from around the world to develop assistive technologies suitable for daily use by people with disabilities.

The competition participants use the latest assistive technologies and equipment to perform various daily tasks. In addition to the competitive sessions, Cybathlon also provides a public platform to promote research in the assistive technology and rehabilitation industry, strengthens dialogue with the public, and promotes the rehabilitation and social integration of people with disabilities.

"I never thought that I could stand at the top of a global competition podium and win the top prize," Xu says, adding that she owes everything to her robotic arm.

Thanks to a sensor worn on the opposite hand, the mechanical wrist, hand and fingers attached to her prosthetic right arm will follow the same movements as those on the left.

"It has a very strong grip strength, and can easily lift objects of up to 10 kilograms," Xu says.

The arm developed by the Chinese team stood out among several strong competitors that came from Sweden, France, Italy, Spain and Indonesia. The mechanical arm on Xu proved its superior strength and efficiency in manual operations.

Hu Xuhui, head of the Chinese team, says he hopes that through this competition, China's achievements in the field of assistive and rehabilitative mechanics for people with disabilities, as well as the achievements made in the rehabilitation of disabled people, will be seen by the world.

"We have creatively added an electric wrist joint on the cable-driven prosthetic arm, which allows for rapid rotation during active opening and closing movements, as well as very easy angle adjustment," Hu explains.

The technical team accomplished freedom of movement in both the hand and wrist, while an accurate body-driven control system was applied to deliver synchronous and rapid control of the arm.

The components connecting the structure of the prosthesis and those in the socket were made through 3D printing.

"It makes the entire mechanical hand lightweight and thus greatly reduces the burden on people with disabilities," Hu says.

"This mechanical hand is as flexible as a human hand, and it can quickly and synchronously use the two joints of the hand and wrist," Hu says.

"That paved the way for completing tasks such as lifting heavy objects and performing dexterous operations in the competition," Hu adds.

Hu, the mastermind of the project, was born in Suzhou, and he became interested in robotics and automation when he was studying electrical engineering in college.

His interest in the subject was stoked when he joined an intelligent car design project in his junior year.

"It involved programming and mechanical design, and I found it fulfilling when I put together a car on my own," Hu recalls.

That was when he went on to pursue prosthetic studies in his postgraduate and doctoral phases at the School of Instrument Science and Engineering at Southeast University in Jiangsu's provincial capital, Nanjing.

"I was told the field involves a lot of automation and robotics research," he says.

As he delved deeper into the subject, Hu was fascinated by the potential of the field and how human-machine interactions might help those in need.

In 2019, Hu got to know Xu, who learned through the Suzhou municipal federation for disabled persons that Hu was looking for a subject for his prosthetic studies.

They talked regularly, either on the phone or through WeChat, so Hu could better understand Xu's prosthetic requirements.

In December 2022, Hu started his postdoctoral research at the Suzhou Institute of Biomedical Engineering and Technology, and he was designing the mechanical arm.

"I wanted it to mimic the functions of a normal human arm, so I invited Xu to try it on," Hu says.

Xu was excited when she heard the news.

The woman whose right forearm was crushed by an industrial punching machine at an electric fan plant in 1992 didn't resign to self-pity, but embraced her fate and made a go of running her own restaurant business in Suzhou.

She started to practice eating, writing and carrying things with just her left hand.

After the plant was shut down, Xu found that her disability hampered her chances of landing a new job, so she opened her business, which has lasted for more than a decade and hires several employees.

Despite her successful business, Xu had always longed for the same mobility she once enjoyed before her accident.

"I bought a nonfunctional prosthetic hand for aesthetic purposes once, but it was really hot to wear it in summer," she recalls.

After readily accepting Hu's offer, she started to frequent the Suzhou institute.

During her interactions with Hu, Xu found the engineer to be very attentive and he constantly adjusted the mechanical hand to ensure her comfort.

"It would feel better each time, and the mechanical arm became more flexible," Xu says.

At the same time, she was in fact doing Hu a big favor.

"In the development process, there were actually many problems, but Xu cooperated with me every step of the way," Hu says.

"She also gave me detailed feedback on the problems she encountered during use, which made my adjustments more precise."

For example, Hu shortened the length of the prosthetic by 2 centimeters based on Xu's height to make it easier for her to fetch things with it.

He also paid special attention to the weight of the mechanical arm, considering Xu often has to carry heavy bags of food for her restaurant business.

In addition, Hu made a point of bringing down the costs, so that the arm is more accessible to a larger number of people in the future.

Currently, the cost of this robotic arm is half that of other prosthetics on the market, according to Hu.

As Xu got increasingly proficient in using the mechanical arm, she and Hu decided to test it at the Cybathlon.

Hu says it has been his goal to participate in international competitions related to the field.

"I can test my work while also being able to see other such designs, both domestic and international," he says.

Although they passed the competition with flying colors this time, Hu says his team has found many areas for improvement in the future.

"For example, the assistive device worn on the left hand could be removed to improve the overall aesthetics for the wearer," Hu says.

Moreover, since people suffer different degrees of injury and amputation, their preferences also vary, making mass production of the arm almost impossible.

Hu says his team will deal with those problems in the future.

"We'll try to satisfy a few subjects first, before reaching out to more," he says.

Currently, the Chinese team is setting its sights on the Cybathlon Challenges 2024, which will present 10 more complex assignments.

Hu considers it an incentive for him and his team to keep optimizing their product.

"We will target the key technology breakthrough points of neural prosthetics and continue to delve into the replication of the movement perception function, enabling the use of more comfortable and affordable smart hands," Hu says.

Hu Xuhui (fourth from right), Xu Min (second from right) and their teammates pose after finishing the Cybathlon Challenges 2023 in Suzhou, Jiangsu province, on March 29. CHINA DAILY  

Xu wears a mechanical arm to pick up bottles in the first-round test of her capacity to lift heavy objects at the competition. CHINA DAILY 

A team member livestreams Xu grabbing small items in a second-round test. CHINA DAILY

(http://epaper.chinadaily.com.cn/a/202304/19/WS643f3376a310b1dea957de72.html)